I have the surplus butt stock for my AO/Kahr M1SB. I also ordered an orginal butt plate with screws which arrived today. After cleaning the cosmoline off it I did a test fit. The stock is slightly wider than the plate - perhaps 1/16" all around. Was this common on the original M1A1s or was the butt stock sanded to fit flush to the butt plate?

I believe I have read somewhere that military Thompson butt stocks were purposely made slightly oversize so when refinished after service use, the wood could be sanded down to fit the size of the butt plate thereby removing all the blemishes and/or damage and still maintaining a serviceable butt stock.